1. Field of the Invention
This invention relates to an apparatus for adapting the diameter of a disk-like recording medium, such as an optical disk, opto-magnetic disk or a magnetic disk, wherein the recording medium is held on the inner periphery of a holder to permit the diameter of the disk-like recording medium to functionally assume the outside diameter of the holder.
2. Prior Art
An optical disk player has been employed in which prescribed information signals recorded on an optical recording medium are read and reproduced by contactless scanning by an optical pickup device adapted for signal reading.
In the above type disk player, the optical disk has only its central non-signal record area clamped by a disk table of a disk driving unit and clamping members securely pressured to the disk supporting side of the disk table. The optical disk is made as one with the disk table and caused to be revolved in unison therewith with the signal record area thereof facing to the optical pickup device.
In the above described disk player having the disk drive unit and the contactless optical pickup device, it is necessary that the disk drive unit mounting the optical disk and the optical pickup device be accurately positioned relative to each other for achieving accurate reading and reproduction of the information signals from the optical disk. Thus, in this type of the disk player, the disk drive unit is supported with accurate positioning by a chassis base plate provided in the main body of the player, while the optical pickup unit is slidably supported on a guide shaft mounted with accurate positioning to the chassis base plate.
Thus the disk loading device in which the optical disk employed in the above disk player is automatically mounted to the disk drive unit is so arranged as to transport only the optical disk for attachment thereof to the disk drive unit.
There is so far known a disk player having a disk loading device such as shown in the Japanese Laid-open Utility Model Application No. 145367/1986 or in the Japanese Laid-open Patent Publication No. 231966/1985.
In the disk player as shown in the Japanese Laid-open Utility Model Publication No. 145367/1986, a disk transfer table 3 on which rests an optical disk 2 is mounted so as to be movable into and out of a main body of the player 1, see FIG. 1. The disk transfer table 3 is transferred into the interior of the main body of the player 1 in the direction shown by the arrow mark a in FIG. 2 by a driving gearing 5 actuated by a driving motor 4 until the optical disk 2 held in an annular recess 6 formed on the table 3 is at a position confronting a disk table 9 of a disk drive unit 8 supported on a chassis base plate 7 within the main body of the player 1, see FIG. 3. A disk supporting member 3a projecting vertically movably from the bottom surface of the annular recess 6 for supporting the optical disk 2 may be actuated so that the optical disk may be placed on and attached to the disk table 9 with a central opening 2a of the optical disk 2 in alignment with the center of the disk table 9. After the optical disk 2 is attached in this manner to the disk table 9, a chucking arm 11 is turned towards the disk table 9 in the direction shown by the arrow mark X in FIG. 3 until a disk clamper 12 attached to the end of the chucking arm 11 is pressured onto the optical disk 2 so that the optical disk may be revolved in unison with the disk table 9.
The optical disk 2 thus clamped to the disk table 9 is confronted by an optical pick-up unit 14 slidably supported by guide shafts 13, 13 mounted to the classis base plate 7.
In a disk loading device of the type in which the optical disk 2 supported on the disk transfer table 3 movable with respect to the main body of the player 1 is mounted on the disk table 9 within the main body of the player 1, it is necessary that the optical disk 2 be supported at the controlled position on the disk transfer table 3, so as to provide for accurate and positive attachment of the optical disk to the disk table 9. To this end, the annular recess 6 formed on the disk transfer table 3 has the radius R.sub.4 corresponding to the radius R.sub.3 of the optical disk 2 supported therein and the outer peripheral surface 2a of the optical disk 2 is supported by the upright peripheral surface 6a of the annular recess 6 to control the support position of the disk 2.
In a disk player shown in the Japanese Laid-open Patent Publication No. 231966/1985, a disk inserting opening 16 is provided in the main body of the player 15, see FIG. 4. In the vicinity of the disk inserting opening 16, there are provided a stationary guide plate 20 and a movable guide plate 19 facing to the stationary guide plate and mounted through the medium of the loading arms 18, 18, rotatably supported by frames 17, 17, see FIG. 5. The optical disk 2 is adapted to be introduced into the main body of the player 15 through a gap formed by these guide plates 19, 20. A pair of rolls, that is, a stationary roll 21 and a driving roll 22, each having a reduced diameter at the center and having the diameter gradually increasing towards both ends, are provided at a position to receive the disk 2 inserted through the gap defined between these guide plates 19, 20. The optical disk 2 is clamped between these rolls 21, 22. The driving roll 22 is transferred onto the disk table 9 of the rotary driving unit 8 mounted in the inside of the main body of the player 15 by a driving electric motor 24 through a drive gearing 23 as shown in FIG. 6 for mounting the disk.
In the above disk player, when the optical disk 2 has been transferred onto the disk table 9, the loading arms 18, 18 are turned to lower the driving roll 22 and the movable guide plate 19 for attaching the disk to the disk table 9 with the central opening 2a of the disk 2 in alignment with the center of the disk table 9. Following the lowering of the roll 22 and the guide plate 19, the chucking arm 11 is turned until the disk clamper 12 provided to the arm end is pressured onto the optical disk 2 so that the disk is clamped for rotation in unison with the disk table 9.
There is also known a disk player in which the optical disk is not clamped automatically to the disk table but in which a cover fitted with a disk clamper in opposition to the disk table of the disk drive device mounted in a substantially vertical position within the main body of the player is mounted for rotation relative to a player cabinet accommodating the main body of the player, so that the disk 2 is clamped for rotation in the upstanding position. The cover is provided with a disk position regulating member adapted for regulating the radial stroke of the disk to provide for an optimum disk clamping by the disk clamper and the disk table. This cover is rotated with the disk placed thereon with the stroke of the disk movement being controlled by the disk position regulating member so that the optical disk is clamped to the disk table.
In the above disk player, the disk position regulating member provided to the cover is provided at a position corresponding to the outer periphery of the disk for coinciding the central opening of the optical disk with the center of the disk table for centering the disk relative to the disk table to regulate the position of the optical disk.
In the above disk players, an optical disk having a predetermined unified disk diameter is necessarily employed. Thus the following problems are presented when an optical disk having different sizes as described above are to be reproduced by the above disk players. In the disk player disclosed in the aforementioned Japanese Laid-open Utility Model Publication No. 145367/1986, disk movement is regulated with the outer peripheral surface 2a of the optical disk 2 abutting on the upright peripheral wall 6a of the annular recess 6 formed on the disk transfer table 3 for matching the disk position relative to the disk table 9. Thus an optical disk other than the optical disk mating with the annular recess 6 cannot be transported at a predetermined support position. Thus disks of different sizes cannot be attached to the disk table 9 with correct centering, so that the disk cannot be clamped by the disk clamper 12 for rotation.
In the disk player shown in the aforementioned Japanese Laid-open Patent Publication No. 231966/1985, the optical disk 2 inserted through the disk inserting opening 16 is clamped by the stationary roll 21 and the driving roll 22 so as to be transferred and attached to the disk table 9 in the main body of the player 15. Thus an optical disk of a size other than a prescribed size cannot be centered with respect to the disk table 9 because the disk 2 then has a variable transfer stroke such that the disk cannot be clamped by the disk clamper 12 for rotation.
In the above described disk player in which the cover is rotatably mounted to the main body of the player and the disk regulated in its position is attached to the disk table, position matching between the disk and the disk player is achieved by having the outer peripheral edge of the optical disk supported as described above. Thus, when an optical disk of a different size is placed on the cover and the latter is turned in a direction to clamp the optical disk, the center of the optical disk cannot be coincided with that of the optical disk or that of the disk clamper and thus correct positioning cannot be achieved. Thus it is not possible to clamp the disk by the disk table and the disk clamper and thus it is not possible to rotate the disk.
There has been proposed an optical disk having a variable size in dependence upon the amount of recorded information. Since the optical disk is capable of recording an extremely large number of information signals, when recording a small amount of the information signals, such as only one or two numbers, the majority of the signal record area remains void or free of recorded signals. Thus an optical disk of a reduced size has been proposed in order to make an efficient use of the disk material and the signal record area so as to provide for simplified handling and to adapt the disk to the amount of the recorded information.
However, such small size optical disk has a drawback that it cannot be loaded in the above described conventional disk layers for recording or reproduction.